RAZIS. Abu Bakr Muhammad ibn-Zakaruya al-Razi, A.D. 865-925, known in Latin as Rhazes, was born in Ray near Teheran, Persia. He was physician, physicist, alchemist, and the greatest clinician of Islam and the Middle Ages. His most important work, an encyclopedia of medicine called Kitab al-tibb al-Mansuri (Al-Mansur's Book of Health), was dedicated to the sultan of Khorasan, al-Mansur. It was translated into Latin as Liber medicinalis Almansoris by Gerard of Cremona in the late twelfth century. Michael Scot used it in his own work, Physiognomica (Physiognomy), in the early thirteenth century. Al-Razi also wrote a famous monograph on smallpox and measles entitled Kitab al-jadari wal-Lasaba in Arabic or De variolis et morbiliis in Latin, sometimes called La Peste and De pestilentia (On the pestilence). It is the oldest description of smallpox. He wrote commentaries on Aristotle's Categories; On Interpretation, a treatise on Aristotle's Analytica priora; a short treatise on metaphysics using commentaries on Aristotle's Physica (Physics); as well as treatises on gynecology, obstetrics, and ophthalmic surgery. Between 1360 and 1385 Merton College owned a copy of the Liber medicinalis Almansoris. [Gerard of Cremona]

Razis, which means in Arabic "the man from Ray," is a byname of location used as a proper name; it appears in the Physician's catalogue of authorities, Gen Prol 432.